Updates to use CreateNetworkStauses from net-attach-def client, bump to v1.7.1

[dougbtv]

NOTE: This functionality is dependent on k8snetworkplumbingwg/network-attachment-definition-client#68 and will require a library update in this PR in order to be complete.

This functionality properly represents Network Status for CNI ADD results that return multiple interfaces themselves.

This approach uses a new method from the net-attach-def-client -- CreateNetworkStatuses, and refactors to account for the array return.

With the previous method, it's somewhat buggy. If multiple pod interfaces are present, it returns the last one -- and groups all of the IP addresses to that address.

For replication of the error yourself, and to see the fix in action, see this gist: https://gist.github.com/dougbtv/1eb8ac2d61d494b56d65a6b236a86e61

For the related suggested update to the NPWG net-attach-def specification, see this proposal @ https://docs.google.com/document/d/1DUTV-o6E6zlRTKZkxeDhAeyGrmq03qPgPbU580Rm7-g/edit

[maiqueb]

/cc

[coveralls]

coverage: 63.857% (+0.7%) from 63.116%
when pulling a28d1e4 on dougbtv:client-lib-multiple-if-cni-result
into 8587734 on k8snetworkplumbingwg:master.

[adrianchiris]

/lgtm

[SchSeba]

LGTM great!

[maiqueb]

Thank you for this.